25,721 research outputs found

    Draft genome sequence of the Streptococcus pneumoniae Avery strain A66

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    We have used HiSeq 2000 technology to generate a draft genome sequence of Streptococcus pneumoniae strain A66. This is a common study strain used in investigations of pneumococcal bacterium-host interactions and was used in the seminal genetic studies of Avery et al

    Structure of a Complete ATP Synthase Dimer Reveals the Molecular Basis of Inner Mitochondrial Membrane Morphology

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    We determined the structure of a complete, dimeric F1Fo-ATP synthase from yeast Yarrowia lipolytica mitochondria by a combination of cryo-EM and X-ray crystallography. The final structure resolves 58 of the 60 dimer subunits. Horizontal helices of subunit a in Fo wrap around the c-ring rotor, and a total of six vertical helices assigned to subunits a, b, f, i, and 8 span the membrane. Subunit 8 (A6L in human) is an evolutionary derivative of the bacterial b subunit. On the lumenal membrane surface, subunit f establishes direct contact between the two monomers. Comparison with a cryo-EM map of the F1Fo monomer identifies subunits e and g at the lateral dimer interface. They do not form dimer contacts but enable dimer formation by inducing a strong membrane curvature of ∼100°. Our structure explains the structural basis of cristae formation in mitochondria, a landmark signature of eukaryotic cell morphology

    CP violation at one loop in the polarization-independent chargino production in e+e- collisions

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    Recently Osland and Vereshagin noticed, based on sample calculations of some box diagrams, that in unpolarised e+e- collisions CP-odd effects in the non-diagonal chargino-pair production process are generated at one-loop. Here we perform a full one-loop analysis of these effects and point out that in some cases the neglected vertex and self-energy contributions may play a dominant role. We also show that CP asymmetries in chargino production are sensitive not only to the phase of mu parameter in the chargino sector but also to the phase of stop trilinear coupling A_t.Comment: 14 pages, 5 figure

    Bone mineral content after renal transplantation

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    Forearm bone mineral content (BMC), as evaluated by photonabsorption densitometry, was measured in 28 cadaver kidney donor recipients who entered the study 8 weeks postoperatively and were followed up for 18 months. BMC decreased signifiantly (p<0.05) but marginally in placebo-treated patients (n=14) (initial BMC 1.09±0.25 g/cm; final BMC 1.05±0.24). Fourteen patients were prophylactically given 1,25(OH)2vitamin D3 in a dose which avoided hypercalcemia and hypercalciuria (sim0.25 µg/day); under 1,25(OH)2 vitamin D3 prophylaxis a significant decrease of forearm BMC was observed no longer (initial BMC 0.94±0.21 g/cm; final BMC 0.95±0.21), but the difference between placebo and 1,25(OH)2 vitamin D3 narrowly missed statistical significance (p=0.066). It is concluded that the decrease of forearm BMC is negligible in transplant recipients with low steroid regimens. The data suggest a trend for prophylaxis with 1,25(OH)2 vitamin D3 to slightly ameliorate forearm (cortical) BMC loss

    Dynamical Polarizabilities of SU(3) Octet of Baryons

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    We present calculations and an analysis of the spin-independent dipole electric and magnetic dynamical polarizabilities for the lowest in mass SU(3) octet of baryons. These extensive calculations are made possible by the recent implementation of semi-automatized calculations in Chiral Perturbation Theory which allows evaluating dynamical spin-independent electromagnetic polarizabilities from Compton scattering up to next-to-the-leading order. Our results are in good agreement with calculations performed for nucleons found in the literature. The dependencies for the range of photon energies up to 1 GeV, covering the majority of the meson photo production channels, are analyzed. The separate contributions into polarizabilities from the various baryon meson clouds are studied.Comment: 10 pages, 7 figures, extended analysis of hyperon polarizabilitie

    Low-energy muon-transfer reaction from hydrogen isotopes to helium isotopes

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    Direct muon transfer in low-energy collisions of the muonic hydrogen Hμ_\mu and helium (He++^{++}) is considered in a three-body quantum-mechanical framework of coordinate-space integro-differential Faddeev-Hahn-type equations within two- and six-state close coupling approximations. The final-state Coulomb interaction is treated without any approximation employing appropriate Coulomb waves in the final state. The present results agree reasonably well with previous semiclassical calculations.Comment: 4 revtex4 page

    Parametric LTL on Markov Chains

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    This paper is concerned with the verification of finite Markov chains against parametrized LTL (pLTL) formulas. In pLTL, the until-modality is equipped with a bound that contains variables; e.g., x φ\Diamond_{\le x}\ \varphi asserts that φ\varphi holds within xx time steps, where xx is a variable on natural numbers. The central problem studied in this paper is to determine the set of parameter valuations Vp(φ)V_{\prec p} (\varphi) for which the probability to satisfy pLTL-formula φ\varphi in a Markov chain meets a given threshold p\prec p, where \prec is a comparison on reals and pp a probability. As for pLTL determining the emptiness of V>0(φ)V_{> 0}(\varphi) is undecidable, we consider several logic fragments. We consider parametric reachability properties, a sub-logic of pLTL restricted to next and x\Diamond_{\le x}, parametric B\"uchi properties and finally, a maximal subclass of pLTL for which emptiness of V>0(φ)V_{> 0}(\varphi) is decidable.Comment: TCS Track B 201

    Dependence of the K x-ray energy upon the mode of excitation

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    The energy of the Ta Kα x rays emitted after electron capture of 181W has been observed to be lower by 0.79±0.06 eV compared to the fluorescent Ta Kα x rays. Similarly, it was found that the Ta Kα x rays emitted after internal conversion following β decay of 181Hf were higher by 0.7±0.1 eV in energy compared to the same fluorescent Ta x rays. The observed effects cannot be explained by the known mechanisms of chemical shift, hyperfine effects, isomer shifts, and shake-off effects alone. Similar observations of the K-x-ray energy shifts in the electron-capture decays of 153Gd and 175Hf with the corresponding fluorescent x rays in Eu and Lu, respectively, can be accounted for by the hyperfine effects, isotope shifts, and chemical shifts
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